A triangular platge of uniform thickness and densilty ismade to rotate about an axis perpendicular to the plane of the paper an a. passing through `A` b. passing through `B`, by the application of some foce `F` at `C` (mid point of `AB`) as show in figure. In which case is angular acceleration more?

Options

A. in case (A)
B. in case (B)
C. both (A) and (B)
D. None of these

Answer

B

Explanation

`tau =Ialpha` or `alpha = tau/I`
Here, as the force is applied at midpoint, `tau_(A) = tau_(B) = F xx L/2`
And as moment of interia depends on the distribution of mass w.r.t., the axis of rotation, hence,
`I_(A) gt I_(B) rArr alpha_(A) lt alpha_(B)` i.e., angular acceleration is more in case (B).